Battery Drain in Disco - D2A

[KEV0044]

G'day :)
My Disco - March '95 D2A - was reluctant to start this morning due to a low battery level .
It's been sitting idle for about three weeks without cranking the engine .
The main battery is less than a year old so should be good .
I put my 'Smart Charger' on it and it was reading around 11 volts (ie -dead for starting a Td5) .
The 'Smart Charger' re charged the battery after a long process but I was wondering how many amps does a D2A use when lying idle for a while ?
cheers :)

[Bearman]

Kev, I dont know a lot about discos, but I do know that if you have an ERPS (electronic rust prevention system ) installed this does happen. I have one in my 110 county and if I dont start it for over 2 weeks the battery is low. They say that they dont draw much power but it is enough to lower the voltage over a couple of weeks. Regards....Brian

[KEV0044]

I know the 'Main Battery' must still power the essentials like - clock - alarm system - ecu - etc - when parked for any period of time .
So there will always be a constant power drain from the battery .
Just interested in how much a D2A draws in power off the battery when it's in this situation .
Thanks .

[AndyRevill]

My guess would be 400 - 500mA but over 3 weeks that's about 250A :( so even half that will flatten the battery

cheers, Andy

[Ean Austral]

Have been told by an Auto lecky that the ABS systems on Disco,s draw power when the car is stopped and will drop the voltage enough so it wont start if left to long.
Cheers Ean

[scarry]

Checked my D2 this morning with a digital clamp meter & it draws .38 of an amp.It hasent been moved for a day or two so will be totally asleep.

I am sure mine started 1st go after not going anywhere for 3 weeks once when we went overseas,but i cant remember for sure.

I am not an auto lecky,but this only equates to total of 8 amps over 21days,so it should do it easy.

I am pretty sure the battery should be around 200a,cant see what mine is without taking it out.

Hope this helps

[drivesafe]

Hi Kev, while there are a few thing that draw power with the engine off, these collectively would not draw more that 20 to 30 milliamps and normally over a three week period should not drain the battery to the point it could not start the motor.

What is more likely to cause these devices to flatten a battery in that sort of time period is if your battery was not fully charged when you last stopped the motor.

Do you have any idea of how much driving time you had done before you left the Disco parked for the three weeks?

[Blknight.aus]

some times if someones setup a system that operates in the same frequecny block as your remotes for the alarm system then the security system doesnt go into "sleep" mode and draws something like half an amp. half an amp for 3 weeks will drop the battery enough that it wont start a disco especially if theres a dodgey earth somewhere thats giving the ECU or the security system the squirts.

[KEV0044]

Do you have any idea of how much driving time you had done before you left the Disco parked for the three weeks?
Hi Tim :)
My Dad's been sick lately so haven't done any long trips since the June long weekend with Redback and Yorkie .
So the disco has only done a few short local trips over the past few months .
Do you think this has contributed to the condition of the battery ?
Thank's .

[AndyRevill]

Checked my D2 this morning with a digital clamp meter & it draws .38 of an amp.It hasent been moved for a day or two so will be totally asleep.

I am sure mine started 1st go after not going anywhere for 3 weeks once when we went overseas,but i cant remember for sure.

I am not an auto lecky,but this only equates to total of 8 amps over 21days,so it should do it easy.

I am pretty sure the battery should be around 200a,cant see what mine is without taking it out.

Hope this helps

A current draw of 0.38A = 9A in 24hrs = 190A in 21 days??? or am I missing something?

[Blknight.aus]

Hi Tim :)
My Dad's been sick lately so haven't done any long trips since the June long weekend with Redback and Yorkie .
So the disco has only done a few short local trips over the past few months .
Do you think this has contributed to the condition of the battery ?
Thank's .

yep and andys got it spot on on the numbers for the current draw. From memory I think the battery in the disco is only good for about 95Ah as a reserve capacity.

[drivesafe]

Hi Kev, that’s the prob and it’s a simple solution. Hook up a battery charger and give the battery a good charge and if the disco is not going to be driven much for a while, about every two weeks charge the battery again.

The battery can hold enough power to start the disco for well over a month, but leaving batteries for that length of time will eventually short the life span, charging the battery two weeks or so will keep the battery not only fully charged but in good nick.

[scarry]

A current draw of 0.38A = 9A in 24hrs = 190A in 21 days??? or am I missing something?

Correct,i must have been dreaming.......

OK,so looking at this calculation,wouldnt the battery be too flat to start the car??
Or is my meter reading incorrect?

[drivesafe]

Hi Scarry, sure your reading wasn’t 0.038, as this would be about spot on.

[Blknight.aus]

Correct,i must have been dreaming.......

OK,so looking at this calculation,wouldnt the battery be too flat to start the car??
Or is my meter reading incorrect?

yep, but that calculation assumes that the vehicle never went to sleep. lets just say it was someones wireless router that was causing the security system to stay "awake" and have a high current draw but they turned it off when they werent home or asleep then you dont have the higher current drain on all of the time.

[goofyr]

Kev, I dont know a lot about discos, but I do know that if you have an ERPS (electronic rust prevention system ) installed this does happen. I have one in my 110 county and if I dont start it for over 2 weeks the battery is low. They say that they dont draw much power but it is enough to lower the voltage over a couple of weeks. Regards....Brian

Yeah this happened to me, I have an ERPS on mine, and when I left it for a couple weeks my battery was flat. Then I noticed that at times, when leaving the battery for a week, the ERPS would flash a red light meaning it was losing power. So when I went on a 5 week overseas trip I simply unclipped the ERPS from the battery. When I came back its started first time.

Cheers,
Randy

[scarry]

Hi Scarry, sure your reading wasn’t 0.038, as this would be about spot on.

no,definitely .38.went up to around 1.2 when the interior lights came on.I was thinking,as i opened the door to release the bonnet catch,maybe this triggered something & it wasnt totally asleep,also it wasnt locked.

I will leave the bonnet open & unlocked o/night & see what it reads in the morning.I am reading the negative wire from the battery,as there are to many positive wires & they are difficult to get to.

[NobbyTD5]

I often leave my D2 TD5 for 4 to 5 weeks without turning it over and no problems...? It does not even sound slow turning it over
cheers
Nobby

[Ean Austral]

I guess we are all asumming the battery was 100% charged when the car was originally stopped!!! and the battery doesn't have a dead plate or 2 Cheers Ean

[Shaker]

There was a post here a while back about an electricity usage monitor in a meter box, like a Cent a Meter, causing a Range Rover battery to go flat.

[Graeme]

yep, but that calculation assumes that the vehicle never went to sleep. lets just say it was someones wireless router that was causing the security system to stay "awake" and have a high current draw but they turned it off when they werent home or asleep then you dont have the higher current drain on all of the time.
The D2's alarm NEVER goes to sleep.
Lock the vehicle with the key (ie alarm not activated) if you want to reduce current draw.

[LandyAndy]

Kev
I constantly have this problem,even worse since fitting a dual battery.
My biggest issue is its less than 1km to work,so big start drain no re-charge.Dark mornings and nights are a nightmare.
Too far to walk to work lugging a 25l esky with the days provisions,nevermind if its raining or hot.
I dont blame the alarm,most of the time its unlocked.
Andrew